The present invention relates to an automated analyzer and a method for conveying a sample rack holding a sample to be analyzed, and more particularly, to an automated analyzer and a method for arranging a plurality of analysis units along a main conveyance line and automatically conveying a sample rack via the main conveyance line.
As examples of arranging a plurality of analysis units along a conveyance line and delivering a sample on a sample rack conveyed by the conveyance line to the analysis unit, for example, Japanese Patent Application Laid-Open Nos. 5-26882, 63-271164, and 7-92171 are known.
Among them, an automated multi-item analyzer disclosed in JP-A-5-26882 uses a method of sequentially transferring sample racks to a conveyance line, stopping the sample rack on the conveyance line, and delivering the sample on the sample rack to an analysis unit. An automated analysis system disclosed in JP-A-63-271164 uses a method in which a circulating path is formed by connecting a plurality of belt conveyors via cross-over rollers, a plurality of analysis units are arranged along the circulation path, the sample rack sent from a rack supplying unit is conveyed by the circulation path, the movement is stopped when the sample rack is positioned in front of the analysis unit, and a sample is delivered from the sample rack on the circulation path to the analysis unit. A vessel conveying system disclosed in JP-A-7-92171 uses a method of arranging a plurality of analysis units along a conveyance line, each analysis unit has a sub-line having an identification information reader, the number of vessels according to an analysis processing ability per a predetermined time of each analysis unit are taken in the sub-line, and the vessel is transferred to the conveyance line after the sample is delivered on the sub-line.
According to the conveying method disclosed in JP-A-5-26882, since the sample is delivered while the sample rack is stopped on the conveyance line, even when the delivery work to the subsequent sample rack is finished, the way of the subsequent sample rack is disturbed until the delivery of the sample of the preceding sample rack for a plurality of analysis items is finished. The subsequent sample rack is not conveyed during such a period and has to wait on the conveyance line.
According to the conveying method of JP-A-63-271164, identification information of a sample rack is read by a bar code reader after the conveyance of the sample rack by the circulation path is started, and the sample rack is conveyed to a relevant analysis unit. However, when the relevant analysis unit is performing the delivery work, the sample rack started to be conveyed has to be stopped on the circulation path, so that the conveyance of subsequent sample racks is disturbed.
According to the conveying method of JP-7-92171, a predetermined number of vessels are sent to the sub-line of the analysis unit according to the analysis processing ability of each analysis unit. After a vessel is sent to the sub-line, however, identification information of the vessel is read and whether the vessel is adapted to a test target of the analysis unit or not is determined. When the vessel is not adapted to the analysis unit, it means that the vessel is conveyed to an unnecessary path for the vessel.